A torpedo was a self-propelled, self-guided weapon. Torpedoes of some type were part of the standard weaponry of most Starfleetvessels in the 22nd to 24th centuries.

Torpedoes were primarily used in space combat as an alternative to directed energy weapons such as disruptors and phasers. Torpedoes could be configured before launch to fit various specifications. Normally a torpedo was equipped with a warhead, and the explosive yield of this warhead could vary depending on the type of torpedo. Torpedo launchers brought the weapon into the launch tube and allowed fire control from the ship's bridge, although a torpedo could be launched manually. (TNG: "Masks"; VOY: "Future's End, Part II") Most of the time a tactical officer was responsible for target acquisition and launch sequence.

The maximum effective range of a torpedo depended on its type. Range was dependent on propulsion and acquisition capabilities. Propulsion was categorized basically by whether the torpedo was warp-capable or used another method of propulsion. Some types of torpedoes were equipped with a self-destruction mechanism. For those types, if a torpedo needed to be aborted and destroyed, due to, for example, a targeting acquisition problem, it could be destroyed.

The torpedo guided itself via internal sensors that could be configured by the tactical officer. (TNG: "Genesis") The advantage was that a firing pattern could be established whereby multiple torpedo launches could be coordinated to hit a single target and thus make the best use of every torpedo's explosive yield. (TNG: "Pen Pals") When necessary, the device's internal sensors could be replaced by specialized sensor packs, allowing for additional flexibility in use; for example, using a sensor pack designed to detect gaseous anomalies could enable a torpedo to lock onto impulse engine emissions. After configuration, the torpedo could be fired and would automatically acquire its target. (Star Trek VI: The Undiscovered Country) Some torpedoes featured advanced artificial intelligence to make the decisions about target acquisition, defensive maneuvers, etc. (VOY: "Warhead")